Degree-square.



Nb.851,94' 7. PATENTED APR. so, 1907.

' L.LALONB.

DEGREE SQUARE.

APPLICATION mum AUG. 21, 1906.

UNITED STATES T OFFIQIEQ LOUIS LALONE, OF SOUTH CHICAGO, ILLINOIS.

DEGREE-SQUARE.

Application filed August 21,

Specification of Letters Patent.

Patented April 30, 1907. 1906- Serial No. 331,519-

To all whom, it nw/y concern:

Be it known that I, LOUIS LALONE, a citizen of the United States, residing at South hicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Degree-Squares, of which the following is a specification.

This invention relates to a drafting instru ment which can be used in place of the regular square and also as a trying square, triangular square and as a degree square.

The object of the invention is a device by means of which the ordinary mechanic may lay out work and ascertain a desired pitch or angle without having to work the problem out by degrees.

The invention consists also of the novel features of construction hereinafter fully described, pointed out in the claim and shown in the accompanying drawings, in which,

Figure 1 is a plan view of the invention, certain binding screws being shown in section. Fig. 2 is a detail enlarged plan of a portion of Fig. l, the binding screw being in section and the cover being shown in position. Fig. 3 is a section on the line 33 of Fig. 2, the square being shown parallel to the base of the rotractor. Fig. 4is a section on the line 4el of Fig. 1.

In these drawings A represents a protractor of the usual form which is provided upon its under face with a depending guide-rib A, as shown in dotted lines in Fig. 1, and in full lines in Fig. 3, the rib being discontinued adjacent the center of the protractor base and one of its inner ends being shown in vertical elevation in Fig. 3.

Upon the curved portion of the protractor is provided with a degree scale A as usual and it is also provided with a scale of inches and fract ons of an inch as shown at A, said scale to be employed upon circles, and it is provided with a third scale A*, indicating the pitch, so that a mechanic unversed in the art of laying off work by degrees can layofl' work by means of the pitch given in scale A.

The base of the protractor at its longitudinal center is cutout as shown at A5 Fig. 3 and a disk B, rotates therein. A screw B having a milled head 13 is placed eccentrically in the outer face of the disk B and a square or straight edge rule O which is longitudinally slotted as shown at C, is held upon the protractor base with one of its side edges in engagement with a side of the screw B, and is held in position by means of a flange cap D through which the screw B cap D is secured to the disk set screw D, which passes loosely through the slot O. The straight edge 0 also carries a threaded bolt E, which extends through the slot C and which has a shoe or fort portion E which engages the under face of the circular portion of the protractor, and a knurled nut E works upon the bolt E and serves to clamp the straight edge G into its adjusted position along the curved portion of the protractor.

It will be obvious from the above con- B is rotated, the

passes and the B by means of a struction that as the disk straight edge will be swung from one osition to another along the scales A A an A and that as the screw B.is mounted eccentrically in said disk, one straight edge of the square 0 will always rest 11 on a radial line extending from the center of the curved portion of the protractor. It will also be .obvious that when, by means of the milled head, B the square has been clamped sulliciently to prevent a movement about the said center, the flange of the cap D bearing upon the pro tractor A, that the square can still be moved longitudinally without rotation of the disk B, and can also be clamped by means of the bolt E and nut against movement in either a lateral or longitudinal direction.

In operation the device is laid upon a drawing board adjacent its edge, and the guide rib A bears against the edge of the board and a meridian or base line is thus established at any desired angle with said line by swinging the straight edge C along the scale A of the protractor, and may be transferred directly to any point 11 011 a plot or diagram on the drawing board from which point the distance on the course or line to be measured may be accurately set o'l'l by means of the graduated scale carried by the rule (J. By the repetition of this operation on all the required courses and distances the plotting is continued until complete without the employment of dividers or independent scales of measurement. The instrument may also be shifted from the first base line to the adjacent edge of the drawing board, when, by setting the rule O to the complementary angle, on the opposite side of the protractor, the plot may be extended to any and every part of the board, or without shifting the rule, a right angle may be obtained with ease and accuracy to the last line.

For ordinary work the protractor base will be about sixteen inches in length and the pivot rule about two feet, but these dimenscrew working loosely through the cap and sions will be varied according to the condithe flange bearing upon the protractor base, tion under which the instrument will be used. a longitudinally slotted rule, and a set screw Having thus fully described my invention, connecting the cap and disk and passing 5 what I claim as new and desire to secure by loosely through the said slot.

Letters Patent, is

A device of the kind described comprising LOUIS LALONE' a fprotractor, a disk mounted upon the center Witnesses: o the protractor base, a set screw eccentric- JOHN C. SOHUBERTH,

1o ally secured in said disk, a flanged cap, the JosEPH AUGsTEN. 

